Taiwan evacuated more than 2,000 tourists on Thursday as the island braced for super-typhoon Soulik, while Japan's Okinawa warned residents that giant waves of up to 12 metres (40 feet) could pound the archipelago.
Taiwan's Central Weather Bureau issued a "land warning" at 1230 GMT, a signal issued when a storm is thought to be 18 hours away from Taiwan.
It said the typhoon would remain a threat to Taiwan although latest information shows its strength has declined slightly in the past few hours.
The typhoon, packing gusts of up to 209 kilometres (130 miles) per hour, was 710 kilometres east southeast of the island's Yilan city in the northeast at 1300 GMT, Taiwan's Central Weather Bureau said.
A weather forecaster told AFP earlier in the day that the typhoon was approaching the island with gusts of up to 227 kilometres per hour, adding, "that means trees could be uprooted and roofs ripped off".
Soulik is moving west-northwest towards Taiwan at about 23 kilometres per hour and could narrowly miss the island or make landfall on its northern tip sometime between late Friday and Saturday morning, the bureau said.
"The public must heighten their vigilance as the typhoon will certainly bring strong winds and heavy rains," the weather forecaster said.
The Taipei-based TVBS news channel said the typhoon was moving along the same route as 1996 super-typhoon Herb, which left 51 dead and 22 missing.
Authorities evacuated 2,300 tourists from Green Island, off the southeastern city of Taitung, and issued a warning to ships sailing north and east of Taiwan to take special precautions.
The Central Emergency Operation Centre also asked the public to stay away from the mountainous areas of central Taiwan, where two recent earthquakes measuring more than 6.0 have struck.
"The soil in the areas has been loosened after the two strong quakes and are prone to landslides," it said in a statement.
The Okinawa weather bureau in Japan warned waves of up to 12 metres and gusts of winds up to 234 kilometres (145 miles) per hour may batter parts of the far southwest of the archipelago.
The westernmost inhabited island of Okinawa lies around 100 kilometres from the east coast of Taiwan.
The local government said while no specific guidance had yet been issued, people should take the usual precautions.
"It is possible that strong winds will blow things around leading to broken windows and the risk of injury," an official said.
"The local government may issue instructions and orders as the typhoon closes in," he added.
The Hong Kong Observatory has classified Soulik as a "super typhoon" on its website because its wind speeds exceed 185 kilometres per hour, while Taiwan's weather bureau listed it as a "strong typhoon".
On the Chinese mainland, meteorological authorities maintained an orange alert—the second-highest level—for Soulik on Thursday, Beijing's official Xinhua news agency reported.
After hitting or passing Taiwan on Saturday Soulik is expected to head towards the coastal provinces of Zhejiang and Fujian, bringing "extremely strong" winds, Xinhua cited the National Meteorological Center as saying.
In August 2009 Typhoon Morakot killed about 600 people in Taiwan, most of them buried in huge landslides in the south, in one of the worst natural disasters to hit the island in recent years.
Explore further: Quakes destroy or damage 83 houses in Philippines